/*
 * Compilation Copyright (c) 1995-2019 by Wei Dai.  All rights reserved.
 *	This copyright applies only to this software distribution package
 *	as a compilation, and does not imply a copyright on any particular
 *	file in the package.
 * 
 *	Boost Software License - Version 1.0 - August 17th, 2003
 *
 *	Permission is hereby granted, free of charge, to any person or organization
 *	obtaining a copy of the software and accompanying documentation covered by
 *	this license (the "Software") to use, reproduce, display, distribute,
 *	execute, and transmit the Software, and to prepare derivative works of the
 *	Software, and to permit third-parties to whom the Software is furnished to
 *	do so, all subject to the following:
 * 
 *	The copyright notices in the Software and this entire statement, including
 *	the above license grant, this restriction and the following disclaimer,
 *	must be included in all copies of the Software, in whole or in part, and
 *	all derivative works of the Software, unless such copies or derivative
 *	works are solely in the form of machine-executable object code generated by
 *	a source language processor.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
 *	SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
 *	FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
 *	ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 *	DEALINGS IN THE SOFTWARE.
 */

// seal.h - originally written and placed in the public domain by Wei Dai

/// \file seal.h
/// \brief Classes for SEAL stream cipher
/// \since Crypto++ 2.2

#ifndef CRYPTOPP_SEAL_H
#define CRYPTOPP_SEAL_H

#include "strciphr.h"
#include "secblock.h"

NAMESPACE_BEGIN(CryptoPP)

/// \brief SEAL stream cipher information
/// \tparam B Endianness of the stream cipher
/// \since Crypto++ 2.2
template <class B = BigEndian>
struct SEAL_Info : public FixedKeyLength<20, SimpleKeyingInterface::INTERNALLY_GENERATED_IV, 4>
{
	CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return B::ToEnum() == LITTLE_ENDIAN_ORDER ? "SEAL-3.0-LE" : "SEAL-3.0-BE";}
};

/// \brief SEAL stream cipher operation
/// \tparam B Endianness of the stream cipher
/// \since Crypto++ 2.2
template <class B = BigEndian>
class CRYPTOPP_NO_VTABLE SEAL_Policy : public AdditiveCipherConcretePolicy<word32, 256>, public SEAL_Info<B>
{
protected:
	void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
	void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
	void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
	bool CipherIsRandomAccess() const {return true;}
	void SeekToIteration(lword iterationCount);

private:
	FixedSizeSecBlock<word32, 512> m_T;
	FixedSizeSecBlock<word32, 256> m_S;
	SecBlock<word32> m_R;

	word32 m_startCount, m_iterationsPerCount;
	word32 m_outsideCounter, m_insideCounter;
};

/// \brief SEAL stream cipher
/// \tparam B Endianness of the stream cipher
/// \sa <a href="http://www.cryptopp.com/wiki/SEAL-3.0-BE">SEAL</a>
/// \since Crypto++ 2.2
template <class B = BigEndian>
struct SEAL : public SEAL_Info<B>, public SymmetricCipherDocumentation
{
	typedef SymmetricCipherFinal<ConcretePolicyHolder<SEAL_Policy<B>, AdditiveCipherTemplate<> >, SEAL_Info<B> > Encryption;
	typedef Encryption Decryption;
};

NAMESPACE_END

#endif
